Certain medical products are packaged directly in a standard syringe body (prefilled syringe), generally made of glass, and closed by a piston which is connected to a plunger for actuating the piston.
The body of a syringe is generally provided with an end for connection to an injection needle, referred to as the injection end, and an end for inserting the piston. It is thus possible to access the substance contained in the syringe via each of said ends, e.g. either by withdrawing the piston from the body of the syringe, or else by expelling or sucking in substance through the needle. It is also possible to access the substance contained in the syringe by means of an injection needle that is pushed through the piston, which is generally made of elastomer, after the plunger has been removed.
A security assembly is already known in the state of the art, in particular from FR 2 799 375 A1 (FR 9912500), for fitting to a syringe comprising a body provided with one end for connection to an injection needle, referred to as the injection end, and one end for inserting a piston, the security assembly being of the type comprising:                a member for fitting onto the body of the syringe in such a manner as to be constrained axially relative to the body; and        a security cap for covering the injection end of the body, the cap having a proximal portion for connection to the fitted member, and a distal portion for releasing the injection end and connected to the connection portion by frangible means.        
After engaging the proximal portion of the security cap on the body of the syringe, the injection end of the syringe body can be disengaged only by rupturing the frangible means. Thus, fraudulent access to the substance contained in the syringe via the injection end of the body of said syringe is revealed by the frangible means being ruptured.
A member for retaining the piston inside the body of the syringe is also known from the state of the art, in particular from DE 29 45 869 A1, said member serving in particular to prevent the piston being withdrawn in untimely or fraudulent manner.